Search

As a wideband radar syrtem, the synthetic aperture radar (SAR) usually confiirts wrth other elertromagnetic syrtems working in the same frequency bands. These iignais, mort of which are natrow-band interference (NBI) for SAR syrtems, severely mterfere SAR syrtems to generate a high-resolution image. Many previous research results focused on the NBI suppresion problem, however, few of them noticed that the NBIs may be time-varying in a local region among different puises, which restricts the suppresion performance of some llasi methods. Hence, in this paper, a graph Lapladan embedding (GLE) algorithm is proposed to suppress NBIs by constructing the Laplaian embedding connertions between different puises of iignais. As a resuk, locally time-varying interferences are embedded in a nonlinear low-dimenional manifold and can be effectively mitigated. The real SAR data measured with NBI are processed, and the resufrs show the effiiency of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Multiple studies have indicated that selective cyclooxygenase-2 (COX-2) inhibitors possess clinically chemopreventive and preclinically anticancer activities. Their long-term use, however, may be limited by the cardiovascular toxicity. This study tried to investigate whether an apple oligogalactan (AOG) could enhance the growth inhibitory effect of celecoxib on colorectal cancer. Caco-2 and HT-29 cell lines were exposed to different concentrations of AOG (0–1 g/L), celecoxib (0–25 μmol/L), and their combination. COX-2 levels were assessed by reverse transcription PCR and Western blot. COX-2 activity was evaluated by measuring prostaglandin E2 concentration. A colitis-associated colorectal cancer (CACC) mouse model was used to determine the effect of the combination in vivo. AOG (0.1–0.5 g/L) could potentiate the inhibitory effect of physiologic doses of celecoxib (5 μmol/L) on cell growth and decrease COX-2 expressions both at RNA and protein levels. In vivo, the combination (2.5% AOG plus 0.04% celecoxib, w/w) prevented against CACC in mice effectively. Our data indicate that AOG could potentiate the growth inhibitory effect of celecoxib on colorectal cancer both in vitro and in vivo through influencing the expression and function of COX-2 and phosphorylation of MAPKs, which suggests a new possible combinatorial strategy in colorectal cancer therapy. [ABSTRACT FROM AUTHOR]

To investigate the electronic and steric influences on enantioselectivities of asymmetric phase-transfer reactions, a series of chiral quaternary ammonium salts were synthesized from cinchona alkaloids and 2-chloromethylbenzimidazole or 1-chloromethyl benzotriazole. Using one of the cinchonine-derived alkaloid catalysts, enantioselective alkylations of N-(diphenylmethylene) glycine tert-butyl ester were efficiently carried out with various alkyl halides to give products in high enantiomeric excess (94-99% ee). [ABSTRACT FROM AUTHOR]

The article discusses the findings of a study which showed the synthesis of doxorubicin (DOX) with α-linolenic acid (LNA). The anti-tumor activity of the DOX-LNA conjugate was analyzed in vitro using different tumor cells, while evaluation of tumor volume and survival time was done through in vivo testing. The research concluded that compared to free DOX, the DOX-LNA conjugate showed lower toxicity as an anti-tumor agent.

Cortex Moutan (root bark of Paeonia suffruticosa Andrew) and Radix Salviae miltiorrhizae (root and rhizome of Salvia miltiorrhiza Bunge) are two herbs widely used in traditional Chinese medicine (TCM) to treat cerebrovascular and cardiovascular diseases. In clinical practice, these two herbs are prescribed together. Studies on the pharmacokinetic interaction between the active constituents of these two herbs (paeonol and danshensu, respectively) can provide substantial foundation for understanding its mechanism and empirical evidence to support the clinical practice. A simple and sensitive high-performance liquid chromatographic (HPLC) method coupled with ultraviolet detector was developed for determination of paeonol in plasma and different tissues (heart, liver, spleen, lung, kidney, and brain) of male Sprague-Dawley rats. When co-administering danshensu, the peak plasma concentration of paeonol was decreased (p < 0.01), the mean residence time (MRT) was prolonged (p < 0.001), the volume of distribution (Vd/F) was increased (p < 0.001), and the concentrations of paeonol in heart, brain, and lung were dramatically increased (p < 0.01 or p < 0.001), compared with these values for rats administered paeonol alone. The results showed that the co-administration of danshensu could alter pharmacokinetic fate and tissue distribution of paeonol in rats, especially in heart and brain, providing substantial foundation for the investigation of the impact of danshensu on paeonol in clinical applications., (© Georg Thieme Verlag KG Stuttgart · New York.)

The conventional chemotherapy agent, doxorubicin, is of limited clinical use because of its systemic toxicity toward normal healthy tissue. A new doxorubicin conjugate with α-linolenic acid showed good anti-tumor activity with lower toxicity than free doxorubicin and exhibited an active tumor-targeting profile due to the introduction of α-linolenic acid which might be an effective tumor-targeting moiety for the modification of chemotherapeutics.